<textarea id="editor"></textarea>
<script>
	CKEDITOR.plugins.add( 'testplugin', {
		requires: 'panelbutton,floatpanel',
		init: function( editor ) {
			editor.ui.add( 'testplugin', CKEDITOR.UI_PANELBUTTON, {
				label: 'test',
				title: 'Test Panel',
				modes: {
					wysiwyg: 1
				},
				editorFocus: 0,
				panel: {
					attributes: {}
				},
				onBlock: function( panel, block ) {
					var keys = block.keys;
					keys[ 39 ] = 'next';
					keys[ 40 ] = 'next';
					keys[ 9 ] = 'next';
					keys[ 37 ] = 'prev';
					keys[ 38 ] = 'prev';
					keys[ CKEDITOR.SHIFT + 9 ] = 'prev';
					block.element.setHtml( '<style>a:focus,input:focus { background-color: red; }</style>' +
						'<a href="#" _cke_focus="1">link1</a><input placeholder="input" _cke_focus="1"><a href="#" _cke_focus="1">Link 2</a>' );
				}
			} );
		}
	} )
	var editor = CKEDITOR.replace( 'editor', {
		extraPlugins: 'testplugin'
	} );

</script>
